EPP-400
Plasma Power Source
Instruction Manual (EN)
0558006924 08/2010
BE SURE THIS INFORMATION REACHES THE OPERATOR.
YOU CAN GET EXTRA COPIES THROUGH YOUR SUPPLIER.
CAUTION
These INSTRUCTIONS are for experienced operators. If you are not fully familiar with the
principles of operation and safe practices for arc welding and cutting equipment, we urge
you to read our booklet, “Precautions and Safe Practices for Arc Welding, Cutting, and
Gouging,” Form 52-529. Do NOT permit untrained persons to install, operate, or maintain
this equipment. Do NOT attempt to install or operate this equipment until you have read
and fully understand these instructions. If you do not fully understand these instructions,
contact your supplier for further information. Be sure to read the Safety Precautions before installing or operating this equipment.
USER RESPONSIBILITY
This equipment will perform in conformity with the description thereof contained in this manual and accompanying labels and/or inserts when installed, operated, maintained and repaired in accordance with the instructions provided. This equipment must be checked periodically. Malfunctioning or poorly maintained equipment
should not be used. Parts that are broken, missing, worn, distorted or contaminated should be replaced immediately. Should such repair or replacement become necessary, the manufacturer recommends that a telephone
or written request for service advice be made to the Authorized Distributor from whom it was purchased.
This equipment or any of its parts should not be altered without the prior written approval of the manufacturer.
The user of this equipment shall have the sole responsibility for any malfunction which results from improper
use, faulty maintenance, damage, improper repair or alteration by anyone other than the manufacturer or a service facility designated by the manufacturer.
READ AND UNDERSTAND THE INSTRUCTION MANUAL BEFORE INSTALLING OR OPERATING.
PROTECT YOURSELF AND OTHERS!
TABLE OF CONTENTS
Section / Title Page
1.0 Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
2.0 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
2.2 General Specications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
2.3 Dimensions and Weight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.0 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
3.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
3.2 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
3.3 Placement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
3.4 Input Power Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
3.5 Output Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
3.6 Parallel Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
3.7 Interface Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
4.0 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
4.1 Block Diagram Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
4.2 Control Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3 Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.4 Arc Initiation Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
4.5 EPP-400 V-I Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.0 Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
5.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
5.2 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
5.3 Lubrication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6.0 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
6.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
6.2 Fault Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
6.3 Fault Isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
6.4 Testing and Replacing Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
6.5 Control Circuit Interface Using J1 and J6 Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
6.6 Auxiliary Main Contactor (K3) and Solid State Contactor Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
6.7 Main Contactor (K1A, K1B and K1C) Activation Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
6.8 Arc Current Detector Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.9 Current Control Pot and Remote Vref . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
6.10 Pilot Arc HI / LO and Cut / Mark Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
7.0 Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
7.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
7.2 Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
4
SECTION 1 SAFETY PRECAUTIONS
1.0 Safety Precautions
Users of ESAB welding and plasma cutting equipment have the ultimate responsibility for ensuring that
anyone who works on or near the equipment observes all the relevant safety precautions. Safety precautions
must meet the requirements that apply to this type of welding or plasma cutting equipment. The following
recommendations should be observed in addition to the standard regulations that apply to the workplace.
All work must be carried out by trained personnel well acquainted with the operation of the welding or plasma
cutting equipment. Incorrect operation of the equipment may lead to hazardous situations which can result in
injury to the operator and damage to the equipment.
1. Anyone who uses welding or plasma cutting equipment must be familiar with:
- its operation
- location of emergency stops
- its function
- relevant safety precautions
- welding and / or plasma cutting
2. The operator must ensure that:
- no unauthorized person stationed within the working area of the equipment when it is started up.
- no one is unprotected when the arc is struck.
3. The workplace must:
- be suitable for the purpose
- be free from drafts
4. Personal safety equipment:
- Always wear recommended personal safety equipment, such as safety glasses, ame proof
clothing, safety gloves.
- Do not wear loose tting items, such as scarves, bracelets, rings, etc., which could become
trapped or cause burns.
5. General precautions:
- Make sure the return cable is connected securely.
- Work on high voltage equipment may only be carried out by a qualied electrician.
- Appropriate re extinquishing equipment must be clearly marked and close at hand.
- Lubrication and maintenance must not be carried out on the equipment during operation.
Enclosure Class
The IP code indicates the enclosure class, i.e. the degree of protection against penetration by solid objects or
water. Protection is provided against touch with a nger, penetration of solid objects greater than 12mm and
against spraying water up to 60 degrees from vertical. Equipment marked IP23S may be stored, but is not intended to be used outside during precipitation unless sheltered.
CAUTION
If equipment is placed on a surface that
slopes more than 15°, toppling over may occur. Personal injury and / or signicant damage to equipment is possible.
Maximum
Tilt Allowed
15°
5
SECTION 1 SAFETY PRECAUTIONS
WELDING AND PLASMA CUTTING CAN BE INJURIOUS TO YOURSELF AND
OTHERS. TAKE PRECAUTIONS WHEN WELDING OR CUTTING. ASK FOR
WARNING
ELECTRIC SHOCK - Can kill.
- Install and earth (ground) the welding or plasma cutting unit in accordance with applicable standards.
- Do not touch live electrical parts or electrodes with bare skin, wet gloves or wet clothing.
- Insulate yourself from earth and the workpiece.
- Ensure your working stance is safe.
FUMES AND GASES - Can be dangerous to health.
- Keep your head out of the fumes.
- Use ventilation, extraction at the arc, or both, to take fumes and gases away from your breathing zone
and the general area.
ARC RAYS - Can injure eyes and burn skin.
- Protect your eyes and body. Use the correct welding / plasma cutting screen and lter lens and wear
protective clothing.
- Protect bystanders with suitable screens or curtains.
YOUR EMPLOYER’S SAFETY PRACTICES WHICH SHOULD BE BASED ON
MANUFACTURERS’ HAZARD DATA.
FIRE HAZARD
- Sparks (spatter) can cause re. Make sure therefore that there are no inammable materials nearby.
NOISE - Excessive noise can damage hearing.
- Protect your ears. Use earmus or other hearing protection.
- Warn bystanders of the risk.
MALFUNCTION - Call for expert assistance in the event of malfunction.
READ AND UNDERSTAND THE INSTRUCTION MANUAL BEFORE INSTALLING OR OPERATING.
PROTECT YOURSELF AND OTHERS!
This product is solely intended for plasma cutting. Any other
CAUTION
use may result in personal injury and / or equipment damage.
CAUTION
To avoid personal injury and/or equipment
damage, lift using method and attachment
points shown here.
6
SECTION 2 DESCRIPTION
2.1 Introduction
The EPP power source is designed for marking and high speed plasma mechanized cutting applications. It can
be used with other ESAB products such as the PT-15, Pt-19XLS, PT-600 and PT-36 torches along with the Smart
Flow II, a computerized gas regulation and switching system.
• 12 to 400 amperes for marking
• 50 to 400 amperes cutting current range
• Forced air cooled
• Solid state DC power
• Input voltage protection
• Local or remote front panel control
• Thermal switch protection for main transformer and power semiconductor components
• Top lifting rings or base forklift clearance for transport
• Parallel supplemental power source capabilities to extend current output range.
2.2 General Specications
EPP-400 400V,
50 / 60Hz CE
Part Number 0558006470 0558006471 0558006472
Voltage 200 VDC
Output
(100 % duty cycle)
Input
* Open circuit voltage is reduced to 360V in the marking mode for 460V and 575V, 60Hz models and to 310V
for 400V, 50Hz model.
Current range DC (marking) 12A to 400A
Current range DC (cutting) 50A to 400A
Power 120 KW
* Open Circuit Voltage (OCV) 423 VDC 427 VDC 427 VDC
Voltage (3-phase) 400 V 460 V 575 V
Current (3- phase) 138A RMS 120A RMS 96A RMS
Frequency 50/60 HZ 60 Hz 60 Hz
KVA 95.6 KVA 95.6 KVA 95.6 KVA
Power 87 KW 87 KW 87 KW
Power Factor 91.0 % 91.0% 91.0%
Input Fuse Rec. 200A 150A 125A
EPP-400 460V,
60Hz
EPP-400 575V,
60Hz
7
SECTION 2 DESCRIPTION
2.3 Dimensions and Weight
114.3 cm
45.00”
94.6 cm
37.25”
102.2 cm
40.25”
Weight = 825 kg. (1814 lbs.)
8
SECTION 3 INSTALLATION
3.1 General
FAILURE TO FOLLOW INSTRUCTIONS COULD LEAD TO DEATH, IN
JURY OR DAMAGED PROPERTY. FOLLOW THESE INSTRUCTIONS TO
WARNING
3.2 Unpacking
CAUTION
CAUTION
• Inspect for transit damage immediately upon receipt.
• Remove all components from shipping container and check for loose parts in container.
• Inspect louvers for air obstructions.
PREVENT INJURY OR PROPERTY DAMAGE. YOU MUST COMPLY WITH
LOCAL, STATE AND NATIONAL ELECTRICAL AND SAFETY CODES.
Using one lifting eye will damage sheet metal and frame.
Use both lifting eyes when transporting with overhead method.
3.3 Placement
Note:
Use both lifting eyes when transporting from overhead.
• A minimum of 1 M (3 ft.) clearance on front and back for cooling air ow.
• Plan for top panel and side panels having to be removed for maintenance, cleaning and inspection.
• Locate the EPP-400 relatively close to a properly fused electrical power supply.
• Keep area beneath power source clear for cooling air ow.
• Environment should be relatively free of dust, fumes and excessive heat. These factors will aect cooling eciency.
Conductive dust and dirt inside power source may cause arc ash-
CAUTION
over.
Equipment damage may occur. Electrical shorting may occur if dust is
allowed to build-up inside power source. See maintenance section.
9
SECTION 3 INSTALLATION
3.4 Input Power Connection
ELECTRIC SHOCK CAN KILL!
PROVIDE MAXIMUM PROTECTION AGAINST ELECTRICAL SHOCK.
WARNING
3.4.1 Primary Power
EPP-400 is a 3-phase unit. Input power must be provided from a line (wall) disconnect switch that contains fuses
or circuit breakers in accordance to local or state regulations.
BEFORE ANY CONNECTIONS ARE MADE INSIDE THE MACHINE, OPEN
THE LINE WALL DISCONNECT SWITCH TO TURN POWER OFF.
Recommended input conductor and line fuse sizes:
Input at Rated Load Input and Ground
Volts Amperes
400 138 95 (4/0) 200
460 120 95 (3/0) 150
575 96 50 (1/0) 125
Rated load is output of 400A at 200V
* Sizes per National Electrical Code for a 90° C (194˚ F) rated copper conductors @ 40° C (104˚ F) ambient. Not more
than three conductors in raceway or cable. Local codes should be followed if they specify sizes other than those listed
above.
To estimate the input current for a wide range of output conditions, use the formula below.
Input current =
(V arc) x (I arc) x 0.688
(V line)
conductor* CU/
mm2 (AWG)
Time delay
Fuse size
(amperes)
Dedicated power line may be necessary.
EPP-400 is equipped with line voltage compensation but to avoid
NOTICE
impaired performance due to an overloaded circuit, a dedicated
power line may be required.
10
SECTION 3 INSTALLATION
3.4.2 Input Conductors
• Customer supplied
• May consist either of heavy rubber covered copper conductors (three power and one ground) or run
in solid or exible conduit.
• Sized according to the chart.
Input conductors must be terminated with ring terminals.
NOTICE
3.4.3 Input Connection Procedure
Input conductors must be terminated with ring terminals sized for
12.7 mm (0.50”) hardware before being attached to the EPP-400.
1. Remove left side panel of the EPP-400
2. Thread cables through the access opening in the rear panel.
3. Secure cables with a strain relief or conduit coupling (not supplied) at the access opening.
1
4. Connect the ground lead to the stud on the chassis base.
5. Connect the power lead ring terminals to the primary terminals with supplied bolts, washers and nuts.
6. Connect the input conductors to the line (wall) disconnect.
2
3
1 = Primary Terminals
2 = Chassis Ground
3 = Power Input Cable Access Opening (Rear Panel)
11
SECTION 3 INSTALLATION
ELECTRIC SHOCK CAN KILL!
RING TERMINALS MUST HAVE CLEARANCE BETWEEN SIDE PANEL
WARNING
WARNING
3.5 Output Connections
AND MAIN TRANSFORMER. CLEARANCE MUST BE SUFFICIENT TO
PREVENT POSSIBLE ARCING. MAKE SURE CABLES DO NOT INTER
FERE WITH COOLING FAN ROTATION.
IMPROPER GROUNDING CAN RESULT IN DEATH OR INJURY.
CHASSIS MUST BE CONNECTED TO AN APPROVED ELECTRICAL
GROUND. BE SURE GROUND LEAD IS NOT CONNECTED TO ANY PRI
MARY TERMINAL.
ELECTRIC SHOCK CAN KILL! DANGEROUS VOLTAGE AND CURRENT!
ANY TIME WORKING AROUND A PLASMA POWER SOURCE WITH COV
ERS REMOVED:
WARNING
• DISCONNECT POWER SOURCE AT THE LINE (WALL) DISCONNECT.
• HAVE A QUALIFIED PERSON CHECK THE OUTPUT BUS BARS (POSITIVE AND NEGATIVE) WITH A VOLTMETER.
3.5.1 Output Cables (customer supplied)
Choose plasma cutting output cables (customer supplied) on the basis of one 4/0 AWG, 600 volt insulated copper cable for each 400 amps of output current.
Note:
Do not use 100 volt insulated welding cable.
12
SECTION 3 INSTALLATION
3.5.2 Output Connection Procedure
1. Remove access panel on the lower front of the power source.
2. Thread output cables through the openings at the bottom of the front panel or at the bottom of the power source immediately behind the front panel.
3. Connect cables to designated terminals mounted inside the power source using UL listed pressure wire connectors.
4. Replace panel removed during the rst step.
Access Panel
3.6 Parallel Installation
Two EPP-400 power sources may be connected together in parallel to extend the output current range.
Parallel power source minimum output current exceeds recommended amounts when cutting below 100A.
CAUTION
Use only one power source for cutting below 100A.
We recommend disconnecting the negative lead from the supplemental power source when changing to currents below 100A. This
lead should be safely terminated to protect against electric shock.
13
SECTION 3 INSTALLATION
3.6.1 Connections for Two EPP-400’s in Parallel
Note:
Primary power source has the electrode (-) conductor jumpered. The supplemental power source has the
work (+) jumpered.
1. Connect the negative (-) output cables to the arc starter box (high frequency generator).
2. Connect the positive (+) output cables to the workpiece.
3. Connect the positive (+) and negative (-) conductors between the power sources.
4. Connect the pilot arc cable to the pilot arc terminal in the primary power source. The pilot arc connection in the supplemental power source is not used. The pilot arc circuit is not run in parallel.
5. Set the Pilot Arc HIGH / LOW switch on the supplemental power source to “LOW”.
6. Set the Pilot Arc HIGH / LOW switch on the primary power source to “HIGH”.
7. If a remote 0.00 to +10.00 VDC current reference signal is used to set the output current, feed the same signal into both
power sources. Connect J1-G (positive 0.00 to 10.00 VDC) of both power sources together and connect J1-P (negative)
of both power sources together. With both power sources operating, the output current can be predicted using the
following formula: [output current (amps)] = [reference voltage] x [100]
Connections for parallel installation of two EPP-400 power sources with both power sources in operation.
EPP-400 EPP-400
S u p p l em e n t a l
Power Source
work
(+)
2 - 4/0 600V
positive leads
to workpiece
electrode
(-)
work
(+)
lead to pilot arc connection in arc starter
box (h.f. generator)
Primary Power
Source
pilot arc
1 - 14 AWG 600V
electrode
(-)
2 - 4/0 600V
negative leads
in arc starter box
(h.f. generator)
14
SECTION 3 INSTALLATION
work
The EPP-400 does not have an ON/OFF switch. The main power is controlled through the line (wall) disconnect switch.
DO NOT OPERATE THE EPP400 WITH COVERS REMOVED.
HIGH VOLTAGE COMPONENTS ARE EXPOSED INCREASING SHOCK
WARNING
WARNING
HAZARD.
INTERNAL COMPONENT MAY BE DAMAGED BECAUSE COOLING
FANS WILL LOSE EFFICIENCY.
ELECTRIC SHOCK CAN KILL!
EXPOSED ELECTRICAL CONDUCTORS CAN BE HAZARDOUS!
DO NOT LEAVE ELECTRICALLY “HOT“ CONDUCTORS EXPOSED. WHEN
DISCONNECTING THE SUPPLEMENTAL POWER SOURCE FROM THE
PRIMARY, VERIFY THE CORRECT CABLES WERE DISCONNECTED. IN
SULATE THE DISCONNECTED ENDS.
WHEN USING ONLY ONE POWER SOURCE IN A PARALLEL CONFIGU
RATION, THE NEGATIVE ELECTRODE CONDUCTOR MUST BE DIS
CONNECTED FROM THE SUPPLEMENTAL POWER SOURCE AND THE
PLUMBING BOX. FAILURE TO DO THIS WILL LEAVE THE SUPPLEMEN
TAL ELECTRICALLY “HOT”.
Connections for parallel installation of two EPP-400 power sources with only one power source in operation.
EPP-400 EPP-400
S u p p l em e n t a l
Power Source
2 - 4/0 600V
positive leads
to workpiece
electrode
Disconnect negative
connection from secondary power source
and insulate to convert from two to one
power source
Primary Power
Source
work
electrode
2 - 4/0 600V
negative leads
in arc starter box
(h.f. generator)
15
SECTION 3 INSTALLATION
3.6.2 Marking with Two Parallel EPP-400’s
Two EPP-400’s, connected in parallel, and can be used for marking down to 24A and cutting from 100A up to 800A. Two
simple modications can be made to the Supplemental Power Source in order to permit marking down to 12A. The modications are necessary only if marking down to 12A is required.
FIELD CHANGES TO PERMIT MARKING DOWN TO 12A:
1. CHANGES TO THE PRIMARY POWER SOURCE: None
2. CHANGES TO THE SUPPLEMENTAL POWER SOURCE:
A. Unplug the WHT wire from the coil of K12
B. Remove the ORN jumper from TB7-11 and connect both ends of the jumper on TB7-12.
OPERATION OF TWO PARALLEL EPP-400’S:
1. Provide Contactor On/O, Cut/Mark, & Pilot Arc Hi/Lo signals to both Primary & Supplemental units for both cutting &
marking. When marking, both power sources are powered up, but the Mark Signal disables the output of the Supplemental Power Source if it has been modied for marking down to 12A. If the Supplemental Power Source has not been
modied, it will provide the same output current as the Primary Power Source.
2. Feed the same V
with a modied Secondary Power Source, the output current transfer function for marking is that of the Primary Power
Source: I
= 50 x V
OUT
installations with an unmodied Secondary Power Source, the output current transfer function for both cutting and
marking is I
OUT
signal into both the Primary & Supplemental units for both cutting & marking. For installations
REF
REF
= 100 x V
. For cutting, it is the sum of the Primary & Supplemental Power Sources: I
.
REF
= 100 x V
OUT
REF
. For
3.7 Interface Cables
Water Cooler Interface (8 Pin)
CNC Interface (24 Pin)
16
SECTION 3 INSTALLATION
3.7.1 CNC Interface Cables with Mating Power Source Connector and
Unterminated CNC Interface
GRN/YEL
RED #4
3.7.2 CNC Interface Cables with Mating Power Source Connectors at Both Ends
GRN/YEL
17
RED #4
SECTION 3 INSTALLATION
3.7.3 Water Cooler Interface Cables with Mating Power Source Connectors at Both Ends
18
SECTION 4 OPERATION
4.1 Block Diagram Circuit Description
Blocking Diodes
L1
Sensor
Left Hall
EPP-400
BLOCK DIAGRAM
NOZZLE
ELECTRODE
Circuit
Pilot Arc
R (snub)
T1
250V Peak
R (boost)
Blocking Diodes
L2
Right Hall
Free Wheeling
Diodes - See Note
T1
425V Peak
Sensor
WORK
Shunt
Precision
Note
Biased Snubber
Circuit
Boost Starting
Arc Contactor
Contact on Pilot
T
contained in the same module.
Both the IGBT’s and Free Wheeling Diodes are
T
Left
See Note
IGBT Modules
Cap.
Bank
Gate
Drive
Sync Signal
For Alternate
PWM
(Master)
Galvanic
Isolator
Left PWM / Gate Drive Board
Gate
Drive
Switching
PWM
(Slave)
Galvanic
Isolator
2
Right PWM / Gate Drive Board
DC Bus
-300V-375V
H
Right
300U120’s
Bus Rectiers
T1 Main
Transformer
See Note
IGBT Modules
See
Note
Current Servo
Twisted Pair
Feedback for Constant
“T” Common Connected to Earth Grounded Work Through the “+” Output
T
Control Circuit
Error Ampliers
Feedback For Fast Inner Servos
Galvanic
Isolator
S
Input
3 Phase
Iout = (Vref ) x (50)
0.0 - 10.0V DC Vref
(Floating)
CNC Common
19
EPP-600 10/20KHz Output RMS Ripple Current Versus Output Voltage
9.0
SECTION 4 OPERATION
4.1 Block Diagram Circuit Description (con’t.)
The power circuit utilized in the EPP-400 is commonly referred to as a Buck Converter or a Chopper. High speed electronic
switches turn on and o several thousand times per second providing pulses of power to the output. A lter circuit, consisting primarily of an inductor (sometimes called a choke), converts the pulses to a relatively constant DC (Direct Current)
output.
Although the lter inductor removes most of the uctuations from the “chopped” output of the electronic switches, some
small uctuations of output, called ripple, remain. The EPP-400 utilizes a patented power circuit combining the output
of two choppers, each providing approximately half the total output, in a manner that reduces ripple. The choppers are
synchronized so that when the ripple from the rst chopper is increasing output, the second chopper is decreasing output.
The result is the ripple from each chopper partially cancels the ripple from the other. The result is ultra low ripple with a
very smooth and stable output. Low ripple is highly desirable because torch consumable life is often improved with low
ripple.
The graph below shows the eect of ESAB’s patented ripple reduction using two choppers synchronized and switching
alternately. Compared to two choppers switching in unison, the alternate switching typically reduces ripple a factor of 4
to 10.
EPP-400 10/20 KHz Output RMS Ripple Current Versus Output Voltage
Choppers Synchronized and Switching in Unison (10KHz Ripple)
Choppers Synchronized and Switchng in Unison (10KHz Ripple)
8.0
7.0
6.0
5.0
4.0
Choppers Synchronized and Switching in Alternately (20KHz Ripple)
Choppers Synchronized and Switching Alternately (20KHz Ripple)
3.0
2.0
RMS Ripple Current (Amperes)
1.0
0.0
0 50 100 150 200 250 300 350
Output Voltage (Volts)
20
SECTION 4 OPERATION
4.1 Block Diagram Circuit Description (con’t.)
The EPP-400 Block Diagram (after Subsection 6.4.4) shows the main functional elements of the power source. T1, the Main
Transformer, provides isolation from the primary power line as well as the proper voltage for the *375V DC Bus. The Bus
Rectiers convert the three phase output of T1 to the *375V bus voltage. A capacitor bank provides ltering and energy
storage that supplies power to the high speed electronic switches. The switches are IGBT’s (Insulated Gate Bipolar Transistors). The *375V bus provides power for both the Left (Master) Chopper and the Right (Slave) Chopper.
Each chopper contains IGBT’s, Free Wheeling Diodes, a Hall Sensor, a Filter Inductor, and Blocking Diodes. The IGBT’s are
the electronic switches that, in the EPP-400, turn on and o 10,000 times per second. They provide the pulses of power
ltered by the inductor. The Free Wheeling Diodes provide the path for current to ow when the IGBT’s are o. The Hall
Sensor is a current transducer that monitors the output current and provides the feedback signal for the control circuit.
The Blocking Diodes provide two functions. First, they prevent the 425V DC from the Boost Starting Circuit from feeding
back to the IGBT’s and the *375V Bus. Second, they provide isolation of the two choppers from one another. This permits
independent operation of each chopper without the other chopper functioning.
The Control Circuit contains regulating servos for both choppers. It also contains a third servo that monitors the total
output current signal fed back from the Precision Shunt. This third servo adjusts the two chopper servos to maintain an
accurately controlled output current commanded by the Vref signal.
The Vref circuitry is galvanically isolated from the rest of the power source. The isolation prevents problems that can arise
from “ground” loops.
Each chopper, the Left Master, and the Right Slave, contain their own PWM / Gate Drive PC Boards mounted next to the
IGBT’s. This circuitry provides the on / o PWM (Pulse Width Modulation) signals to drive the IGBT’s. The Left (Master) PWM
provides a synchronized clock signal to its own Gate Drive circuitry as well as to the Right (Slave) Gate Drive circuitry. It is
through this synchronized signal that the IGBT’s from the two sides switch alternately reducing output ripple.
The EPP-400 contains a Boost Supply for providing approximately 425V DC for arc starting. After the cutting arc is established, the Boost Supply is turned o with a contact on the Pilot Arc Contactor (K4).
A Biased Snubber reduces the voltage transients created during cutting arc termination. It also reduces the transient voltages from a parallel power source thus preventing damage to the power source.
The Pilot Arc Circuit consists of the necessary components for establishing a pilot arc. This circuit disengages when the
cutting or marking arc is established.
* The Bus voltage for the 400V, 50Hz model is approximately 320V DC.
21
SECTION 4 OPERATION
4.2 Control Panel
K
A - Main Power
I
H
F
J
G
A
C
B
D
E
L
Indicator illuminates when input power is applied to the power source.
B - Contactor On
Indicator illuminates when the main contactor is energized.
C - Over Temp
Indicator illuminates when power source has overheated.
D - Fault
Indicator illuminates when there are abnormalities in the cutting process or when the input line voltage falls outside of
the required nominal value by ±10%.
E - Power Reset Fault
Indicator illuminates when a serious fault is detected. Input power must be disconnected for at least 5 seconds and then
reapplied.
F - Current Dial (Potentiometer)
EPP-400 dial shown. EPP-400 has a range of 12 to 400 A. Used only in panel mode.
22
SECTION 4 OPERATION
4.2 Control Panel (con’t.)
G - Panel Remote Switch
Controls the location of current control.
• Place in the PANEL position for control using the current potentiometer.
• Place in REMOTE position for control from an external signal (CNC).
H and L - Remote Connections
H - 24 pin plug for connecting the power source to CNC (remote control)
L - 8 pin plug for connecting the power source to the water cooler
I - Pilot Arc HIGH / LOW Switch
Used to select amount of pilot arc current desired. As a general rule, for 100 amperes and below, a setting of LOW is used.
This can vary depending on gas, material and torch used. High/Low settings are specied in cutting data included in the
torch manual. When the EPP-400 is set to marking mode, this switch must be in the low position.
I
H
F
J
G
A
C
B
D
E
K
L
23
SECTION 4 OPERATION
4.2 Control Panel (con’t.)
J - Meters
Displays voltage and amperage when cutting. The ammeter can be activated when not cutting to view an estimation of
the cutting current before cutting begins.
K - Actual/Preset Switch
The ACTUAL AMPS / PRESET AMPS spring return toggle switch, S42, defaults to the ACTUAL (UP) position. In the ACTUAL
position, the OUTPUT AMMETER displays the output cutting current.
In the PRESET (DOWN) position, the OUTPUT AMMETER displays an estimate of the output cutting current by monitoring
the 0.00 to 10.00 VDC cutting or marking current reference signal (Vref). The reference signal comes from the CURRENT POTENTIOMETER with the PANEL/REMOTE switch in the PANEL (UP) position and from a remote reference signal (J1-J / J1-L(+))
with the PANEL/REMOTE switch in the REMOTE (DOWN) position. The value displayed on the OUTPUT AMMETER will be the
value of Vref (volts) times 50. For example, a reference signal of 5.00V will result in a preset reading of 250 Amps on the meter.
The switch may be changed to and from the ACTUAL and PRESET positions at any time without aecting the cutting process.
DANGEROUS VOLTAGES AND CURRENT!
ELECTRIC SHOCK CAN KILL!
WARNING
BEFORE OPERATION, ENSURE INSTALLATION AND GROUNDING PRO
CEDURES HAVE BEEN FOLLOWED. DO NOT OPERATE THIS EQUIP
MENT WITH COVERS REMOVED.
24
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